Sealing fuel tanks?

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heisan
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Sealing fuel tanks?

Unread post by heisan » Sun Dec 06, 2009 6:30 pm

My Raven has an aluminium fuel tank. Today I leak tested it before fitting, and discovered a number of tiny leaks. Two main sources though: pinhole leaks in welds, and leaks through/around rivets.

What would be the best way to seal it? Slosh some sealant around the inside, or slap some PRC on the outside? Any other options?

Are there local sources for PRC, or whatever gets used for sloshing the tank?

Thanks!
Justin
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Re: Sealing fuel tanks?

Unread post by Theuns v V » Sun Dec 06, 2009 7:31 pm

heisan wrote:Are there local sources for PRC
Get hold of the folks at Buck Rodgers Aviation in midrand.(google them for tel no). I used their sealer on the cub's tanks and no problems so far.

T
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Re: Sealing fuel tanks?

Unread post by RudiGreyling » Mon Dec 07, 2009 10:19 am

I'll give you my untested opinion and 2nd information just so that you can ask the right questions to the right people.

1) I would try and fix it on the inside with proseal PRC, depending on location I might even consider cutting another access hole and plugging it after.
2) Sloshing compound can work, but I am hearing rumors about sloshing compound and MOGAS not agreeing with each other in the USA over time.
3) Trying to wick a thin sealant from outside might work, but what you'll need you need to ask the experts and report back.

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Re: Sealing fuel tanks?

Unread post by heisan » Mon Dec 07, 2009 10:28 am

RudiGreyling wrote: 1) I would try and fix it on the inside with proseal PRC, depending on location I might even consider cutting another access hole and plugging it after.
Didn't even think of that :oops: ... All the leaks I have found so far should be accessible from the inside (although with a long stick, and a steady hand).

Let's see what can be done!
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Re: Sealing fuel tanks?

Unread post by Axwund » Sat Dec 12, 2009 8:05 am

Heisan

I was given advice for my leaking tank to use 3m product called EC776 which is a sloshing compound specifically for aviation.

I have sealed my tanks with it, but will fully test them when I get back from Angola.


I bought a liter of EC 776 from TP Agencies in Edenvale around R400p/l

www.tpagencies.co.za
011 6093531

Have a look at the following link

http://www.microlighters.co.za/viewtopi ... 13&t=10752
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Re: Sealing fuel tanks?

Unread post by Ploughman » Sat Dec 12, 2009 8:20 am

Axwund wrote:Heisan

I was given advice for my leaking tank to use 3m product called EC776 which is a sloshing compound specifically for aviation.

I have sealed my tanks with it, but will fully test them when I get back from Angola.


I bought a liter of EC 776 from TP Agencies in Edenvale around R400p/l

http://www.tpagencies.co.za
011 6093531

Have a look at the following link

http://www.microlighters.co.za/viewtopi ... 13&t=10752
We used the stuff on the DC-3 tanks in the SAAF and nothing beats it. Dilute with MEK and slosh in tank for 30 min, then drain over night......NO MORE LEAKS
Last edited by Ploughman on Sun Dec 13, 2009 7:19 am, edited 1 time in total.
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Re: Sealing fuel tanks?

Unread post by Ray W » Sat Dec 12, 2009 11:43 pm

T. van Vuuren wrote:
heisan wrote:Are there local sources for PRC
Get hold of the folks at Buck Rodgers Aviation in midrand.(google them for tel no). I used their sealer on the cub's tanks and no problems so far.

T
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Re: Sealing fuel tanks?

Unread post by GooneyBird » Sat Dec 19, 2009 8:57 am

Agree that EC776 is good stuff - have also used it on DC-3 and 4 tanks with good results. For PRC (suspect you will need the 896 A2 or A 1/2) contact Safomar http://www.safomar.co.za/) and speak to Leon. I have just redone the Catalina's tanks with their products and can confirm that their price and service are excellent compared with other suppliers. Expect to pay around R1000 per tin for PRC. When using it, I suggest you clean the surface very well using MEK, (Methyl Ethyl Ketone) (this can be had from Protea Chemicals in Jhb) before applying anything. Other stuff you may consider purchasing when using PRC will be a good mask (especially for the MEK), some surgical gloves (PRC sticks to skin and nails very well), material to clean old sealant off the inside of the tanks (making a scraper from an old piece of perspex or micarta works well) and scotchbrite pads.

Remember to seal any fasteners with PRC too. If there are any rivets that are leaking don't be tempted to boppa them up - you'll only make it worse, rather remove the skin/repair, clean and reseal and rerivet it altogether. For interest, there are several types of external PRC available as well - generally sneered at in this country, but if used correctly, very effective.
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Re: Sealing fuel tanks?

Unread post by Morph » Thu Jan 07, 2010 5:43 pm

Make sure they supply you MEK (pronounced M E K) as opposed to MEK-P (pronounced mek pee) which is readily available at any store that supplies Fibreglass. MEK-P is used for curing the epoxy in fibreglass and leaves a oily residue that never appears to dry. It is essentially MEK with peroxide added. I got supplied the wrong stuff and it created havoc. Had to clean it all out and start again.

I had cracks along the top seam of my fibreglass tank, so I removed the wing, added the EC776, rotated the wing until the stuff was over the leak and left it to stand for 24 hours. Works like a dream, leaves a rubbery flexible layer. NOTE: Alcohol in fuel can dissolve it, so avoid lead replacement fuels that contain alcohol
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Re: Sealing fuel tanks?

Unread post by Luscombe47 » Sat Jan 09, 2010 8:16 pm

I have build two aluminium tanks with rivuts for my luscombe in August 07. The sealing compound I have used is Flamemaster, ( C 53204B2PT was the serialnumber on the tin) It never hardens totally and is certified for fuel. Obtianed it from Placo Wonderboom. +- R250 for a tin that was enough for both tanks (45 litres each) It is a soft putty like substance wich are mixed with activater and takes at least 48 hours to form a sealeant. I fly mostly on Mogass and had no problems of any kind ever since :D . I can really recomend it though it is a sticky mess to work with. You are welcome to PM me if you need more info.
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Re: Sealing fuel tanks?

Unread post by Stertsleper » Sun Jan 24, 2010 5:43 pm

HI Heisan if the tank is still outside , why not weld it again ??

heisan wrote:My Raven has an aluminium fuel tank. Today I leak tested it before fitting, and discovered a number of tiny leaks. Two main sources though: pinhole leaks in welds, and leaks through/around rivets.

What would be the best way to seal it? Slosh some sealant around the inside, or slap some PRC on the outside? Any other options?

Are there local sources for PRC, or whatever gets used for sloshing the tank?

Thanks!
Justin
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heisan
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Re: Sealing fuel tanks?

Unread post by heisan » Sun Jan 24, 2010 11:14 pm

Stertsleper wrote:HI Heisan if the tank is still outside , why not weld it again ??
The leaks are not just on the welds - also on two riveted seams. All over, a decent sloshing compound will probably do a better job.
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